Shuttle Investigators Seek Clues in West

Published 7:00 pm, Wednesday, February 12, 2003

AP Science Writer

Investigators into the space shuttle disaster still believe important clues might be found in west Texas and points even farther west _ even though no debris has yet been found.

The reason for their faith in the absence of evidence is a wealth of credible photographs, video recordings and eyewitness reports from California, Nevada, Arizona and New Mexico. More than 1,500 photographs and videos of Columbia's re-entry have poured in to NASA.

Many bolster the notion the shuttle Columbia already was shedding debris several minutes and hundreds of miles before its fiery breakup over Texas.

But so far, NASA has ruled out more than 100 of the 179 credible reports of possible debris found west of Fort Worth. And the agency has no data indicating it was already in trouble as it made landfall after crossing the Pacific Ocean.

"We're trying to pin down those seemingly credible reports that something was happening before the telemetry told us," Adm. Harold Gehman Jr., chairman of the nine-member board investigating the cause, said this week.

For example, there is this description from amateur astronomer Bill Sorrells, who has watched several returning shuttles.

"I saw it was noticeably different from the others that I had seen _ not in a spectacular way, in a subtle way," said Sorrells, who watched from below the peak of Mount Hamilton outside San Jose, Calif. It was eight minutes before mission control lost contact with the crew.

"On this occasion it was a completely different color," he said. "I was expecting that same pinkish-purple color I had seen before. I felt the trail it left behind was wider and brighter."

Not long after, California Institute of Technology astronomer Anthony Beasley saw several flashes in Columbia's tail from where he watched, farther to the east, in Bishop, Calif.: "We could see there were things clearly trailing the orbiter subsequent to that," he said.

Still, no debris from the 234,000-pound spacecraft has been recovered from California _ or anywhere west of Fort Worth _ even though objects like thermal tiles could have survived to fallen to earth, debris experts said.

NASA is particularly interested in finding any pieces _ particularly tiles _ that were among the first to be ripped from Columbia. Loss of the tiles in key spots on the shuttle would have left it vulnerable to the searing heat of re-entry.

Shortly after Beasley spied Columbia, and just before it passed north of Las Vegas, mission control in Houston received the first sign of trouble.

"FYI, I have lost four separate temperature transducers on the left side of the vehicle _ the hydraulic return temperatures," Jeff Kling, maintenance and crew systems officer, told the flight director.

The shuttle and its seven-member crew continued gliding toward a planned touchdown in Florida even after the sensors had blinked out one by one.

Soon, more problems cropped up, including increased drag on the left wing and apparent loss of pressure in the shuttle's tires. Then, Houston lost contact at 7:59 a.m. CST.

The investigation board said it has begun stitching together the audio recordings along with photographs, radar and data from Columbia itself to reconstruct a timeline of the doomed shuttle's final minutes.

The mosaic may also include readings from earthquake instruments capable of recording the boom of the spacecraft's breakup and the subsequent cascade of debris hitting the ground.

"It's a jigsaw puzzle. We're assembling a giant puzzle," Gehman said.

Investigators hope the project will allow them to pinpoint areas to look for more debris _ places that have yet to yield clues of Columbia's destruction.